Railway traffic controlling apparatus



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RAILWAY TRAFFIC CONTROLLING APPARATUS Filed DSC. 31, 1936 6 Sheets-Sheet 5 W W 1,3 M j* l @QD-J :76 777g Mgg/P @a-ii 57:10 awp 519W# W IRK R W 5 K R I iX CQH i: 51115K 155 ES FH, 5%

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RAILWAY TRAFFIC GONTROLLING APPARATUS Filed 1366.731, 1936 6 Sheets-s116642 G @HR 26H5 5TP 201 I 202 u 229 126K v EBJB I ?HR +2 LIEF@ R A 4BR -Hs f- 206 2 5 C 2 50 K @204 auf, 28 542W 16 4CGP @CGP HIS' ATTORNEY Patented June 3, 1941 RAILWAY TRA'FFIC lCONTROLLENG APPARATUS John M. Pelikan, Greentree, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application December 31, 11936, Serial No. '118,609

(Cl. l)24S-134) 59 Claims.

My invention relates to railway traffic controlling apparatus, and more particularly, to an interlocking control system for governing the movement of trafiic through a track layout comprising a plurality of track sections interconnected by track switches which may be variously arranged to form different traffic routes.

One object of my invention is the provision, in a system of this character, of an illuminated diagram of the track layout in the signal cabin or other point of control, which visually indicates different traffic routes through the track layout as these are established by the operator, and which also indicates the progress of trains over such routes. Another object of my invention is the provision of an all-relay route interlocking system for operating the switches and signals for the different traiiic routes under the control of manually operable contacts, push buttons or the like, which are preferably mounted on the track diagram in locations corresponding to the ends of the respective routes. A further object of my invention is the provision of means whereby one or more of the track switches may be operated as required to establish a route by operating the two push buttons at the opposite ends of the representation of that route on the track diagram, and in which one or the other of the two signals for governing the movement of tramo over that route will then clear automatically, the traffic direction established being dependent upon the relative order of the operation of two push buttons. Other objects, purposes and features of my invention will be pointed out as the description proceeds.

My invention is an improvement upon that disclosed in a copending application, Serial No. 14,868, for Interlocking control apparatus, filed April 5, 1935, by Earl M. Allen and Howard A. Thompson.

I will describe four forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

Referring to the accompanying drawings, Figs. lA to 1H, inclusive, taken together, illustrate diagrammatically the circuits for a route interlocking system embodying one form of my invention, together with a plan of the track layout to be controlled, shown in the upper portion of Fig. 1E, and a suitable control panel, shown in Fig. 1A, which contains a track diagram constituting a miniature representation of the track layout. Fig. 2 shows the additional circuits that are required when an intermediate signal such as signal l2 is included in the track layout. It is to be understood, therefore, that the second form of my invention includes the apparatus of the first form together with that of Fig. 2, and that in the first form the intermediate signal l2 is to be omitted and the relays directly associated therewith are idle and may be omitted as hereinafter pointed out in detail. Figs. 3A and 3B illustrate an alternative method of route selection which may be used when there are two or more different routes between the same route ends. The third form of my invention is illustrated by the drawings for the iirst form together with Fig. 3B, but with the apparatus of Fig. 3A substituted for the corresponding portion of Fig. 1C. Fig. 4 illustrates a modiiication of one of the push button circuits of Fig. 1B, whereby the operation of only the push button at the exit end of a route is required to establish a route and to clear the signal for an approaching train. The fourth form of my invention is therefore illustrated by substituting the circuits of Fig. 4 for one or more of the corresponding circuits of Fig. 1B in the first form of the apparatus. Fig. 5A is a side view, in section, and Fig. 5B is a planview, in section, of a preferred form of the structure for illuminating the unit portions of the track diagram of Fig. 1A.

Similar reference characters refer to similar parts in each of the several views.

In order to simplify the description, I will first explain the functions of the several parts of the first form of my apparatus, and will then describe its operation under selected conditions in detail, and will then point out the distinguishing features of the other forms of my apparatus.

The track switches shown in the track plan of Fig. 1E, in accordance with the usual notation of the signaling art, are identified by odd numbers, such as 1, 3 and 5, andthe wayside signals by even numbers, such as 4 and 8. For the guidance of the control operator, the corresponding numbers are shown on the control panel of Fig. 1A, adjacent the switches of the diagram and the respective control buttons. The two switches of a crossover bear the same number but are distinguished by the suffixes A and B, respectively, and similarly, in case of a multiple arm signal, the suix A designates the top arm or high speed signal, B designates a medium speed signal, and C a slow speed signal. Each bottom arm C also serves as a call-on signal which may be cleared to admit a train to an occupied block. The one arm signals 2, lil and I2 are slow speed signals governing train movements against the normal direction of traic.

In the circuit plans, each relay is identified by a letter or combination of letters, prefixed by the designation of the switch or signal with which it is associated, and in order to enable the circuits to be more readily understood, they are arranged in the written circuit form with similar circuits grouped together in the same view. In circuits of this form the relay contacts are not necessarily adjacent the respective relays which operate them, and a contact is identified notonly by a number but more particularly by showing the designation of the relay which operates it above the contact. Furthermore instead of showing the local source of current for energizing the relays, I have shown only the terminals, which are designated by the reference characters B and C, referring to the positive or supply terminal and to the negative or common return terminal, respectively, of the source.

The push buttons of the control panel of Fig.

1A bear the reference character P, and the circuits which they control directly are grouped together in Fig. 1B. The even-numbered push buttons dP, 8P, etc., are the route buttons located in the track diagram at the ends of the different routes, and each is provided with a normally open contact which may be closed by pressing the button, to energize a push button stick relay PS. Each route button also has a normally closed contact which may be opened by operating it in the opposite direction, that is, by pulling the button, to effect the manual release of the associated stick relay PS, as required. Each route button therefore constitutes a centrally biased three-position manually operable circuit controller, and these are not necessarily of the push button form, but a twist key or centrally biased rotatable lever may also be used. Each stick relay PS controls a directional route stick relay RS, the circuits for which are also shown in Fig. 1B. Each relay RS is of relatively high resistance or its otherwise arranged so as to be of the slow pickup type. Each call-on signal is governed by a call-on stick relay COS shown in Fig, 1B, and each relay COS is controlled by n a call-on button CP, mounted in the lower part of the control panel directly below the corresponding route button. The apparatus also includes means for operating the track switches or Crossovers individually, comprising normal and i' reverse switch stick relays NWS and RWS shown in Fig. 1B, which are controlled by the push buttons NP and RP of the control panel. The latter are similar in construction to the route buttons, and each may be pressed to operate a l switch or may be pulled to cancel the individual switch control.

Fig. 1C shows circuits controlled by the stick relays PS and the route relays RS, comprising a. route network consisting of interconnected circuits so arranged as to include a route circuit for each route through the track layout. Each route circuit includes a switch operating relay NR or RR for each switch of the route which relays when energized cause the operation of the switches to normal or reverse as required for the route. Each route circuit also includes a signal control relay HR at each end, one or the other of which is included in the circuit when energized in order to selectively clear the signal for one direction or the other when the route is established.

One feature of my invention relates to the control of the route circuits of Fig. 1C by the successive operation of the push buttons P for the two ends of a route. When the push button for the entrance end of a route is operated, the corresponding relays PS and RS become successively energized. Relay RS picks up before the operator presses the second button and then connects one terminal of the local source of current through the winding of the associated signal control relay HR .to those route circuits which have one end at that point, thereby establishing that end as the entering end of the route. Each route relay RS is energized over a back contact of one or more of the switch operating relays NR or RR which are in series in the route circuits which that relay RS controls, and these series relays are of relatively low resistance and are quick acting in comparison with relays RS. When the push button P at the exit end of any one of the route in question is operated, the corresponding relay PS picks up, thereby completing the selected route circuit to energize the relay HR at the entrance end. Relay RS at the exit end of the route although energized momentarily does not pick up because its circuit is immediately opened by the operation of the adjacent series relay in the energized route circuit, while the relay RS at the entrance end having already completed its stick circuit remains energized. It follows, therefore, that each route is established by the successive operation of the push buttons to energize the relays PS for the two ends of the route, and that the tramo direction is determined by the energization of relay ER at one end or the other in accordance with the relative order in which the two push buttons are operated.

In addition to the manual means for cancelling a route already mentioned, means are provided in accordance with a feature of my invention for deenergizing each route circuit automatically as soon as it is entered by a train, by opening the stick circuit for the relay PS at the entering end. This is accomplished in such a manner that the stick circuit again becomes available after a time sumcient to insure the release of the route relays, so that an occupied route may be reestablished by a second operation of the same push buttons, and then a call-on signal may be cleared by operating the corresponding push button CP. This arrangement permits a train to enter, at slow speed, a route already occupied by a preceding train, as is often desirable in practice.

Fig. 1D shows the circuits controlled by the signal control relays HR of Fig, 1C, comprising a network of interconnected circuits for controlling the signals. Each signal arm bearing a reference character in Fig. 1E has an operating mechanism bearing the reference G with identifying prex in Fig. 1D, those signal arms having no references being fixed markers. Each mechanism G is controlled over a signal circuit which corresponds to the route which such signal governs and which includes contacts of the corresponding switch operating and indication relays as well as a front contact of a locking relay LS controlled by the opposing signal for the same route. The signals may be of any desired type, but as herein illustrated, it is to be understood that they are of the well-known scarchlight type having a mechanism G of the form disclosed in the E. J. Blake Reissue Patent No. 14,940, of August 31, 1920. Each signal is provided with the usual back lock or signal indication relay GP, which, as shown in Fig. 1D, is energized only when the corresponding signal indicates stop. For simplicity, each signal is arranged to indicate either clear or stop, and the usual circuits for controlling each signal by the next signal in advance to provide a third indication have been omitted. It is to be understood, however, that the third indication may be provided in the system disclosed by means which are well known and which form no part of the present invention,

Referring now to Fig. 1E, the track plan shown therein represents the tracks rails lav and Ib of each oi two main tracks interconnected by crossovers l and 5, the lower track being also connected to a siding by a single switch 3. While a speciiic track layout is disclosed, it is to be understood that the apparatus of my invention is adapted to control other track layouts that may involve entirely diierent combinations of switches and signals, the present layout having been chosen to illustrate the principles of my invention in a simple manner. As indicated in the drawings, the tracks are divided into sections by insulated joints, the detector sections of the upper track which include the track switches being designated by the references lT and 5T, while those of the lower track bear the references 3T and 1T. The adjacent approach sections of the two main tracks are designated 3T and 11T, respectively. Each track section is provided with the usual closed track circuit including a track battery 9 and a normally energized track relay, each track relay being identied by the reference TR with a numerical prei-lx identifying the track section to which it corresponds. Each approach section track relay controls an approach relay AR. Each detector section track relay controls a track repeating relay TP, and each relay TP controls a slow release repeating relay TZ.

Relays TP and TZ jointly control the hereinbefore-mentioned circuits for effecting the automatic release of the routes.

Each track switch of Fig. 1E is actuated by a power-operated switch machine SM, which as herein disclosed may be understood to be of the type shown in the Zabel Patents Nos. 1,293,290 and 1,413,280. Each switch machine is provided with the usual motor having its operating circuits controlled by the contacts of a polarized switch control relay WR in the manner illustrated in the Willard Patent No. 1,380,452, as indicated diagrammatically by dotted line connections in the drawings, and it is to be understood that each switch or switches will be operated to normal, as shown, or to reverse, when the control relay WR is energized and its polar contacts are closed to the left or right, respectively. Each relay WR is controlled by the switch operating relays NR and RR of Fig. 1C, when route control is used, or by the switch stick relays NWS and RWS of Fig. 1B, when individual switch control is used. Each relay WR is also controlled by a switch locking relay LR. The locking relays LR are controlled in turn by the detector track relays TR and by the approach locking relays LS and section locking relays ES and WS of Fig. 1F.

Each switch machine is provided with the usual switch circuit controller as disclosed in the Zabel patents hereinbefore referred to, for controlling a polarized switch indication relay WP, as indicated diagrammatically by dotted line connections in the drawings. For an understanding of the present invention it will suffice to point out that when both switch machines SM of the crossover l or 5 are locked normal or reverse, the corresponding relay lWP or SWP will be energized and its polar contacts closed to the left or right, respectively, and that relay SWP is similarly controlled by switch machine BSM for the single switch 3.

Each switch indication relay WP is provided with a pair of repeating relays NWP and RWP each of which is energized only when the polarized relay WP is energized in a position correspondingjzo that of the associated switch control relay WR.

As will be hereinafter pointed out in detail, the locking relays LR together with the switch indication relays NWP and RWP control the route circuits of Fig. 1C in such a manner that a route circuit cannot be completed unless each switch of a route is either unlocked or already occupies a position in accordance with that route. The indication relays NWP and RWP also control the signal circuits of Fig. 1D.

Referring now to Fig. 1F, an approach locking relay LS is provided for each signal, and each relay LS is so controlled by the indication relay GP for the associated signal that it can be energized only when that signal is at stop. Time release of the locking is provided by means of a time element relay TE' for each relay LS, these being of the well-known thermal type, and each relay TE is governed by an associated stick relay TES. The locking relays LS function in a wellknown manner to provide the usual time and approach locking of the switches and of opposing signals; thus when a signal is put to stop Inanually, the energization of the associated relay LS is delayed for a predetermined time interval, or until the associated relay TE completes its cycle of operation; this delay is nullied by the release of the corresponding track relay TR if the signal is put to stop by a passing train, and also, in the case of the high speed signals 4A and 8A, if there is no train approaching and the corresponding approach relay AR is energized. Each relay LS, as shown, controls a section locking relay ES or WS, which relays provide the usual directional control of the switch locking and function so that when a train enters a route the locking of each switch ahead of the train will be maintained while the locking of each switch in the rear of the train will be released as soon as the corresponding track section is vacated.

Fig. 1G shows the circuits for a group of directionally controlled stick indication relays ESK and WSK which control lamps for illuminating the tracks of the tra-ck diagram of Fig. 1A. The relays ESK and WSK are controlled by the signal control relays HR and function in such a manner that when one of the route circuits of Fig. 1C is energized, a series of these relays for the correspending direction east or west become energized successively in tandem, including one relay for each track section of the corresponding route. Each route indication relay has a stick circuit controlled by a back contact oi the track repeater relay TP for the corresponding track section, so that it will remain energized after a train has entered the route and until that section is vacated.

Referring now to the track diagram of Fig. 1A, it will Abe seen that the track sections are represented by a plurality of indicators K each comprising a substantially linear portion or strip, which as herein illustrated, is `constructed as shown in Figs. 5A and 5B, and consists of a moulded member of clear glass fitting in a slot in the face of the control panel and provided at the rear with an enclosure which in the case of the detector track indicators contains a white lamp W and a red lamp R, the approach indicators AK being provided with red lamps only. Each of the moulded glasses is provided with a facing of opal glass to render it translucent or semi-opaque so that the-track portion will be more readily seen by reflected light when not illuminated, and also to diiuse the transmitted light so as to provide uniform illumination when lamp W or R is lighted.

Fig. 1H shows, in the upper part, the circuits for the lamps of the track diagram, and it will be seen that the white lamps W are controlled by one or more of the indication relays ESK or WSK over front contacts of the track repeater relays TP, while the red lamps R are similarly controlled over back contacts of relays TP. Furthermore, those portions which represent the branch tracks extending in the trailing direction from a track switch are also controlled by the switch indication relays NWP and RWP and by the switch stick relays NWS and RWS, and these portions serve as switch indication lamps when the switches are controlled individually.

The track diagram is normally dark, but when the operator presses the two buttons at the end or" a route, the energization of a relay HR which results if the route is available causes the energization in tandem of a corresponding series of relays ESK or WSK, thereby lighting the white lamps for these portions of the diagram corresponding to the parts of the route that are already established. As the operated switches respond, the white lamps for the corresponding switch indicating portions of the track diagram become lighted, so that a substantially continuous illuminated white line corresponding to the established route is displayed as soon as the route is fully established. When a train enters the approach section, the red lamp for that section is lighted, and as the train enters each detector section of the route, the illumination of the corresponding portions of the diagram changes from white to red, and as each section is vacated, the corresponding portions become dark.

The track diagram also includes an indicator K for each signal, each comprising a green lamp G and a red lamp R, which in the form illustrated are located adjacent the push button for the entering end of the route which the signal governs, the circuits for these lamps being shown in the lower part of Fig. 1H. When the push button relay PS for the entering end of a route is operated, the adjacent red lamp is lighted. This lamp remains lighted if the route is not available. When the route becomes established and the corresponding signal has been cleared, the red lamp is extinguished and the corresponding green lamp is lighted.

The signal indication lamps are arranged to be controlled also by an interrupter relay CT, so as to provide additional information by the display of flashing indications. Thus each slow speed signal when clear causes the display of a iiashing green light, while each high or medium speed signal when clear causes the display of a steady green light. When a signal is put to stop manually, the switch locking will in some cases remain eiective for a predetermined time interval as already explained, and during this interval the operator will be unable to establish a conicting route. In order to aid the operator in setting up the new route as soon as it becomes unlocked, the circuits are so arranged that the red signal indicating lamp will ash from the time when a route is manually cancelled until the locking is released, and will then become dark.

I will now describe the operation of the first form of my apparatus under different assumed conditions, tracing the circuits in detail. I will rst assume that the apparatus is in the condition shown in the drawings, and that the operator desires to pass an approaching train from section 4T, Fig. 1E, over route 4-8 to section 8T. When the train enters section 4T the release of track relay lETR opens contact Il, deenergizing the approach relay SIAR, which relay releases and closes back contact I3, Fig. 1H, to close a circuit for the red lamp R of the approach indicator liAK, this portion of the track diagram of Fig. 1A being thereby illuminated to inform the operator of the approach of the train.

To set up route 4 3, the operator will first press button 5P for the entering end and then will press button 6P for the exit end of the route. The momentary operation of button 4P completes a circuit for relay QPS which may be traced in Fig. 1B from terminal B, contact I4 of button .IP, relay 4PS, back contacts I5 and I6, in multiple, of relays 3RR and RR to terminal C. It is to be noted that relay IPS is non-responsive if route 6-8 is set up and relays 3BR and SRR are both energized, in which case no route governed by button il? is available. In the present instance these relays are released and therefore relay IPS picks up and closes a stick circuit from terminal B, contact I'I of button 4P, front contact I oi relay "ITP, back Contact I9 of relay IWSK, front Contact 2li and winding of relay APS, contacts I5 and I6 in multiple to terminal C. This stick circuit serves to hold relay GPS energized until the train enters the route and contact I8 opens, or until the route is cancelled manually by opening contact I'l. Relay IiPS closes a circuit from terminal B, back contacts 2| and 22 of relays IBNR and IRR, front contact 23 of relay APS, relay SRS to terminal C. Relay PS also closes a circuit for indicator 4K, Fig. 1H, which may be traced from terminal B, front contact 24 of relay lPS, back contacts 25 and 26 of relays IRR and IBNR, red lamp R of indicator 4K to terminal C, for lighting lamp R to display a red light at the entrance to route 4 3 on the track diagram.

Relay GRS picks up in about one-half second after becoming energizedi which it is to be understood is before the exit button 8P is operated, and relay RS then closes its stick circuit from terminal B over contact 21, Fig. 1B, and also closes contact 28, Fig. 1C, connecting terminal C through relay 4I-IR to the left-hand end of three route circuits comprising those for route 4--I8, route 4-8 over crossover 5 reversed, and route 4--3 over crossover I reversed, respectively. Without tracing these circuits in detail, it will be apparent from the drawings that the rst includes relays IBNR, 3NR, SBNR and back contact 158 of relay I AGRS and is open at front contact 29 of relay HIPS; that the second includes relays IBNR, SNR, ERR, and back contact IES of relay SRS and is open at front contact 30 of relay BPS and also at back contact 3l of relay 4PS, while the third includes relays IRR and EANR and back contact ISB of relay SRS and is open only at front contact 3@ of relay SPS.

When button 8P for the exit end of route 4-8 is operated, relays BPS and BRS will be energized over circuits shown in Fig. 1B which are similar to those already traced for relays lIPS and GRS, but as soon as relay SPS closes its front contact 30 the third ,of the above-mentioned route circuits is completed to terminal B and relays IRR @and 5ANR pick up quickly in series with relay GHR. Relay EANR opens back contact 32, Fig, 1B, in the pickup circuit for relay 8RS `loefore this relay has time to pick up and relay BRS therefore remains released and its back contact I69 in the route circuit remains closed. Relay BPS closes front contact 33, Fig. 1H, in the circuit for lamp R of indicator 8K for the exit end of the route, lout `back contact 34 of relay 5ANR opens to prevent this lamp from becoming lighted. Back Contact of relay IRR in the circuit for lamp R of indicator 4K for the entrance end of the route also opens, but this lamp is now energized over a @branch circuit which extends from terminal B, front contacts 35, 36 an-d 37 of relays HCGP, AGP, and @RS through lamp R to terminal C.

It will loe noted that the energized route circuit for route 4 8 is now disconnected from the rest of the route network. Relay IRR, being energized, opens back contacts 38 and 39 in the branches which include relays IANR and IBNR, respectively, while relay 5ANR opens back .contact 46 in the branch which includes relay 5RR. Relay IRR also opens `back contact 5I, Fig. 1B, in the circuit for relay ZPS. It follows that the energized route circuit can not be interfered with by anattempt to set up a conflicting route, and that back contacts 62, 43, 44 and 45 of relays IANR, IBNR, ZPS and BRR in the route circuit for route 5 8 are held closed. As hereinbefore stated, it is to be understood that signal I2 is omitted from the rst form of the apparatus.A

The associated relays IZXS, IEPR, 2 8HS and IHS are therefore idle, and the back contacts of these relays shown in the energized route circuit remain closed, and in practice Would be replaced ;by jumper connections in this form of the apparatus. The energized route circuit also includes back contact 46 of relay 5RWS, the function of which Will be described later, and front Icontacts #il and I8 of the switch locking relays ILR and 5LR, the latter .contact being :bridged by a front contact 59 of relay ENWP which is closed rbecause crossover 5V is normal. It will be apparent, therefore, that in this instance the route circuit for route 4 6 will become energized in response to the operation of buttons ISP Y and 8P even though relay 5LR is deenergized because the crossover I is not locked and because crossover 5 already occupies a position in accordance with the route.

When the r-oute circuit became energized, relay IRR closed its front contact 56, Fig. 1E, completing the reverse energizing circuit -for relay IWR from terminal B, front contacts 59 and 5I of relays IRR and ILR, relay IWR, front con'- tact 52 of relay ILR, `back contacts 53, 54 and 55 of relays IBNR, IANR and INWS to terminal C. Relay IWR reverses and operates the switch machines IA SM and IB S1VI to reverse crossover I, and also opens its left-hand polar contact 55 to release relay INWP. At the same time, re-

lay 5ANR closes its front -contact 51 to complete Relay IESK upon becoming energized, closes contact 59 to complete a pickup circuit :for relay IESK from terminal B over front contact 60 of relay IRR, relay IESK to terminal C, and the latter relay picks up and completes a pickup circuit for relay SESK from terminal B over its front contact 5I and iront contact 62 of relay EANR, relay 5ESK to terminal C. Relay 'IESK upon becoming energized closes contact 63, Fig. 1H, to .complete a circuit from terminal B over front contact 64 of relay 'ITP to light the white lamp W for portion 'IK of the track diagram, and `similar circuits are closed over contacts 65 and of relays IESK and ITP, and over contacts 6l and 69 of relays 5ESK and 5TP to light the lamps W for .portions IK and 5K, respectively, while lamp W for portion 5ANK is lighted over the circuit from terminal B, front contact 61 of relay 5ESK, ,back :contact 59 of relay -5NWS, front contacts 'I0 and 'II `of relays `5NWP and 5TP, lamp W to terminal C. A circuit is prepared for lamp W of portion IRK from terminal B, front contact 'I2 of relay IESK, back contact 'I3 of relay IRWS, front contacts 14, I5 and 'I6 of relays IRWP, lTP and ITP, lout contact 14 is open and an incomplete route is indicated on the track diagram because portion IRK remains dark.

When the crossover switches IA and IB complete their movement and are locked reverse, the switch indication relay IWP rbecomes energized in the reverse direction, completing a circuit shown in Fig. 1E which extends from terminal B over its neutral contact I'I and reverse contact "I8, relay IRWP, reverse vcontact 56 of relay IWR to terminal C. Relay IRWP upon :becoming energized closes its contact l above mentioned to light lamp W for portion IRK, thereby completing the route indication so as to display a substantially continuous illuminated white line on the track diagram comprising a representation of route 4 8.

The energization of relays tIHR, IRR and ANR also -prepared a circuit for the signal mechanism IICG, shown in Fig. 1D, which is completed upon the energization of relay IRWP. This circuit may be traced from terminal B, front :contact 'I9 of relay 8LS,1ba-ck contacts 8i] and 8l of relays BHR and B IZTES, front contacts 82 and 83 of relays 5ANR and 5NWP, thence over back contacts of relays IZHS, 2 8HS and IZXS (which contacts in practice are replaced by a jumper when si-gnal I2 is not used), thence over back contact 64 of relay ZTES, `front contacts 85 and 66 of relays IRWP and IRR, `back contact B'I of relay llTES, front contacts 88, 89 and 90 of relays II-IR, IRWP and AGP, mechanism 40G, front contact 9i of relay IHR to terminal C. Mechanism tCG therefore becomes energized to cause signal 6C to indicate proceed at slow speed and its back contact 92 opens to deenergize the back lock relay ECGP. Y

Relay IICGP, upon releasing, opens contact 93, Fig. 1F, to release the approach locking relay lLS. Relay IILS upon releasing opens contact 94 to release the section locking relay IES, and relay "IES, by opening contact 55 releases relay IES, since contact 96 of relay INWP is now open. Relay IES is used only when signal I2 is not used, and in the first form of the apparatus it is to be understood that its contact 51a, Fig. 1E, replaces contact 9Iu of relay I2LS in the circuit for relay 5LB. Relay IES upon releasing opens contact Sie to release BLR, locking crossover 5 normal, while relay ILS opens contact 98 to release relay ILR, locking crossover I reversed. Switch 3 is not locked because the open contact 99 of relay 'IES in the circuit for relay 3LR is now .bridged by the closed front contact of relay IRWP. The energized route circuit for route li--S remains closed because contact I1 of relay ILR, Fig. 1C, is now bridged by the closed contact ||l| of relay IRWP.

When relay IICGP releases, its Contact 35, Fig. 1H, opens to extinguish the red lamp for the signal indicator 4K and a circuit is closed from terminal B, back contact |52 of the interrupter relay CT, back contact ID3 of relay 4CGP, lamp G of indicator @K to terminal C. Relay CT has an energizing circuit including its own back contact |04 and operates repeatedly to open its contacts at regularly recurring intervals. Indicator 4K therefore display a hashing green indication when signal r4C is cleared. It will also be noted that if signal 4A had been cleared, IICGP would have been energized, and relay lIAGP released, and in this case, lamp G of indicator 4K would have been energized from terminal B over front contact and back contact 35 to display a steady green indication.

Referring now to Fig. 1B, it will be seen that a stick circuit for relay SPS for the exit end of the route is now closed from terminal B, contact |95 of button SP, front contacts |06 and |01 of relays EESK and ltANR, front contact |58 and winding of relay SPS to terminal C. Relay llPS is now held J energized over the stick circuit including back contact |53 of relay 1WSK as already described, and may be released manually by opening contact Il of button IiP. Relay IPS releases automatically when a train enters the route and contact I8 of relay 'ITP opens. It will also be noted that the individual switch control relays INWS, IRWS, SNWS and SRWS are now non-responsive to the operation of their respective push buttons, because contacts I 59 and I I5 of relays ILR and 5LR are open.

I will now assume that the approaching train passes signal C at clear and enters track section 1T. Track relay ITR releases, opening contacts III and H2, Fig. 1E, in the circuits for relays if" 1TP and ILR. Relay ITP releases and opens contact ||3, deenergizing the slow release relay 1TZ, and also opens contact I8 to release relay IiES. Relay SRS then releases, then relays IRR, EANR and BPS release, and then the slow acting relays dHR and 'ITZ release. Relay 4HR opens contacts BIE and 9|, Fig. 1D, deenergizing mechanism CG to restore signal QC. to stop, whereupon contact S2 closes, re-energizing relay dCGP. Relay CGP closes contact 93, Fig. 1F, completing a pickup circuit for relay @LS which may be traced from terminal B, contacts 93 and |I4 of relays liCGP and AGP, back contacts |I5, IIE and II'I of relays ATE, fiCOS, and 1T?, relay 4LS to terminal C. Relay ltLfS picks up, closing its stick circuit from terminal B over contacts 53 and I I4 of relays ICGP and IIAGP, contact |I8 and winding of relay lLS to terminal C. Relay 4LS closes contact 98 in the circuit for relay ILR, but relay ILR is now held released by the open contact ||2 of relay 1TR. When the train enters section IT, relay ITR releases and opens contacts IIB and |20 in the circuits for relays ITP and ILR, and relay ITP releases and deenergizes relay ITZ. When the train vacates section 1T, relays 1TR, 1TP and ITZ pick up. Relay 1ES then picks up over the circuit from terminal B, contacts 94 and I2| of relays llLS and 1TP, relay 'IES to terminal C and closes its stick circuit from terminal B over contact 94 and its own front contact |22, and contact 95 of relay 1ES in the circuit for relay IES becomes closed. When the train enters section 5T, relay ETR releases and opens contacts |23 and E24 in the circuits for relays STP and SLR, and relay STP releases and deenergizes relay 5TZ. When the train vacates section IT, relays I'I'R, ITP and I TZ pick up, and the closing of Contact |25 of relay ITR causes relay ILR to become energized, thereby releasing the locking for switches IA and iB as soon as the train passes out of section IT. Relay IES now picks up over the circuit .from terminal B, contacts |25, 95 and |26 of relays ELS, 'IES and ITP, relay IES to terminal C, and closes its stick circuit from terminal B over contacts |25 and 95 of relays 2LS and 1ES and its own front contact |21. Contact 91a of relay IES in the circuit for relay 5LR now closes, but relay SLR does not become re-energized until the train vacates section 5T and contact |24 of relay 5TR closes.

It will be apparent from the foregoing that the apparatus of my invention provides sectional route locking which functions in such a manner that the operator may set up a new route, such as route II-I Il, or route IEB-4, in the case illustrated, as soon as section IT is vacated, but that crossover 5 remains locked normal until section 5T is Vacated. It is also to be noted that each switch control relay WR is maintained energized while locked by the deenergization of the associated relay LR, for example, relay IWR has a normal and reverse holding circuit including its front neutral contact |28 and its normal or reverse polar contacts |29 and V|3I) and back contacts 5| and 52 of relay ILR, which is effective to maintain relay IWR energized in its last operated position when relay ILR is deenergized. It follows that relay IWR is conditioned to supply current to switch machines IA--SM and IB-SM over contacts |28, |29 and |35 to restore the track switches to their last operated position if they should become dis placed by a passing train.

Considering now the operation of the indication apparatus in response to a train movement over route 4 8, it will be noted that the signal indicator 6K becomes. dark when the train enters section 1T. This is because when relay lICGrl? picks up, it opens contact |63, Fig. lI-I, to deenergize lamp G, and relay ARS has released to open contact 31 in one circuit for lamp R, While relay ftPS has released to open front contact 24 in the original energizing circuit for lamp R. Although back contact 24 closes, Contact |3I of relay 4LS in series therewith is opened when relay ALS picks up. The approach indicator IIAK becomes dark when the train vacates section 4T and relay AR picks up, as is obvious. The release of relays eI-IR, IRR and SANR opens the pickup circuits for the energized indication relays ESK of Fig. 1G, but relay lESK is now held energized over a stick circuit from terminal B over back contact E33 of relay 1TF- and its own front contact |32. Relay IESK is nowy held energized over a stick circuit from terminal B over contacts 59 and |35 of relays ESK and IRWP and its own front contact |34, while relay SESK is held energized over a stick circuit from termlnal- B over front contact 5I of relay IESK, back contact |31 of relay 5RWP and its own front contact |36. The release of relay 'ITP also opens front contacts 64 and 15, Fig. 1H, and closes back contacts 15 and |38, energizing the lamps R to cause the indication of the track portions 1K and IRK to change from white to red, while the white lamps of the indicators IK, EANK and K for the sections ahead of the train remain lighted.

When the train enters section IT, relay ITP releases to complete a new stick circuit for relay IESK from terminal B over back contact of relay ITP and its own front contact |39, and relay ITP opens front contact 6B and closes back contact I4I to change the indication of the track portion IK from white to red. When the train vacates section 1T, relay 'IESK releases and opens contact 63 to cause portion 'IK to become dark. When the train enters section 5T, relay 5TP releases to complete a new stick circuit for relay EESK from terminal B over back contact |43 of relay ETP and its own front contact |42, and relay 5TP opens front cont-acts 63 and 7| and closes back contacts II and |44 to change the indication of track portions 5ANK and 5K from white to red. When the train vaca-tes section IT, relay IESK releases and opens contacts 'I2 and 65 to-cause portions IRK and IK to become dark. When the train enters section 8T, lamp R of the indicator SAK becomes lighted.

Finally, when the train vacates section 5T, contact 6l of relay 5ESK opens to cause portions EANK and 5K to become dark, and when it vacates section 8T, portion SAK becomes dark, thereby restoring the track diagram to its normal dark condition.

It will be noted that at least one red lamp for each track section, such for example, as the one controlled over back contact |38 of relay ITP, becomes lighted when the corresponding track section is occupied even though no route has been set up. These lamps therefore in addition to indicating the movement of a train over an established route also indicate the release of a track relay and the consequent locking of the switches under other conditions, such for example, as would occur if a car should drift into a detector track section past a stop signal.

It is believed that in View of the foregoing detailed description of the operation of the apparatus under one set of conditions that its operation under other corresponding conditions will be readily apparent without further explanation. It is obvious, for example, that if buttons 4P `and 8P are operated in the reverse order, route -II will be set up and signal 8C will clear for a train movement from section 8TV to section 4T, and also that, any non-conilicting route such as route E I or route It-B, may be set up at the same time without interference by the operation of the proper buttons. Furthermore, if buttons 4P and IGP are operated instead of buttons 4P and 8P, route 4-I will be established and signal 4A will clear, and in this case, indicator 4K will display a steady green indication instead of the flashing indication displayed when the slow speed signal 4C is cleared.

I will next assume that the operator is unable to complete route 4 8 as described, due to failure of one of the switches iA or IB to complete its movement to reverse, as would be the case,

for example, if there was an obstruction in the switch. In such a case the operator employs the individual switch control buttons, but iirst pulls buttons 4P to open contact Il' to cancel the route setup, which restores the individual control by releasing relay IRR to close back contact 50, Fig. 1E. He then presses button INP, Fig, 1B, closing a circuit from terminal B, contact |59 of relay ILR, contact of button INP, relay INWS to stick circuit from terminal B, contact |09 of relay ILR, back contact |46 of relay |RWS, front contact |4I of relay INWS, normal contact |48 of button INP, relay INWS to terminal C. Relay INWS upon becoming energized completes the normal energizing circuit for relay IWR, Fig. 1E, over its front contact 55 and back contacts 5I! and of relays IRR and IRWS. If switches IA and IB respond and become locked normal, relay INWP will become energized, completing the normal indication circuits for crossover I to illuminate portions IANK and IBNK of vthe track diagram, the circuit vfor lamp W of portion IANK extending from terminal B, Fig. 1H, over front contacts |49, |50 and I5| of relays INWS, INWP, and ITP, lamp W to terminal C, while that for portion |BNK is similar and includes front contacts |52, |53 and |54 of relays INWS,

INWP and. ITP.

terminal C, energizing relay INWS to close its If the operator now presses button IRP, relay IRWS will become energized, opening back contact |46 to release relay INWS to extinguish the normal indication lamps and closing front contact |55, Fig. 1E, to complete the reverse energizing circuit for relay IWR. If switches IA and IB now fully respond and become locked reverse so that relay IRWP picks up, a reverse indication circuit is closed over front contact 'I3 of relay IRWS to light lamp W of portion IRK of the track diagram. The operator may now operate buttons 4P and 8P to clear signal 4C as already described, whereupon the remaining lamps W for the route portions of the track diagram will become lighted, and relay IRWS will be released when contact |09 of relay ILR opens, cancelling the individual control.

It will be apparent from the foregoing that the two portions of the track diagram which extend in the trailing direction from the representation of the switch serve in place of the usual switch indication lamps when the switch is operated individually. 3RK serve to indicate the normal and reverse positions of switch 3, respectively, while in the case of crossover I, as described, the two parallel portions IANK and IBNK provide the normal indication and portion IRK provides the reverse indication.

I will next assume that the operator wishes to set up the secondary route 4-8, over crossover 5 reversed, as would be the case, for example, if he was unable to complete the route set-up for route 4 8 over crossover I reversed but succeeded in restoring crossover I to normal. In this case he operates the individual switch control button ERP, energizing relay SRWS, to close contact |51, Fig. 1E, to complete the reverse energizing circuit for relay EWR to reverse crossover 5. Relay 5RWS also opens back contact 4B, Fig. 1C, in the route circuit which includes relays IRR and EANR, and closes front contact 46 in the secondary route circuit which includes relays IBNR, SNR and ERR. In this instance the latter circuit will be completed over contacts 28 and Sil of relays 4RS and GPS, when buttons 4P and 8P are operated, and then relay 5RR will open back contact |55, Fig. 1B, to prevent relay BRS from picking up. Relay 4HR becomes energized over the secondary route circuit, and when crossover 5 is locked reverse, the energization of relay 5RWP completes the corresponding signal circuit for mechanism 40G which may be traced in Fig. 1D from terminal B, contacts 19, 8|] and 8|; thence over the lower branch including contacts |58, |59, |55 and IGI of relays 5RWP, SRR,

Thus portions SNK and BNR and IBNR, contacts 81, 88, |93, |94 and 9|) of relays A'I'ES, lll-IR, INWP, SRWP and 4AGP, mechanism GCG, contact 9| to terminal C. Mechanism SCG upon becoming energized releases relay llCGP to lock the route. In this case, relayv SLS is released by relay ACGP to deenergize relays ILR and TES, as before, but since contact l of relay IRWP, Fig. 1E, is now open, the opening of contact 99 of relay 'IES releases both relays SLR and SLR. Relay SLR upon releasingr opens contact H9, Fig. 1B, to release relay SRWS, dropping contact 45, Fig. 1C, but the original or so-called preferred route circuit is now Open at back contact 4S of relay SRR and the new or secondary route circuit is held closed over front contact |63 of relay SRR.

The locking of crossover I is released in the present instance when the train vacates section lT, and relay 'ITR picks up to close contact H2 in the circuit for relay ILR. When relay lTP closes its front contact |2|, relay TES picks up, closing contact 99 in the circuit for relays 3LR and SLR. Relay 3LR becomes energized when the train vacates section 5T and relay 3TR picks up to close contact |52, While relay SLR remains deenergized until the train vacates section ST and contact |24 of relay STR closes.

Considering now the operation of the indication apparatus in the case described, relay IHR upon becoming energized will close ccntact 58, Fig. 1G, to pick up relay IESK Relay 'EESK then closes a pickup circuit from terminal B over its own contact |64 and Contact |85 of relay IBNR, relay SESK to terminal C, and relay SESK picks up and closes a pickup circuit from terminal B over its own contact |63 and contact |61 of relay SRR. relay SESK to terminal C. Remembering that relays lNWP and ENWP are now energized, it will be clear from Fig. 1H, that the lamps W for portions 1K, iBNK, BNK, 3K and 5K of the track diagram will be lighted and that lamp W for portion SRK will become lighted when relay SRWP becomes energized, to display a complete route indication, and that the illumination of the .successive portions will change from white to red and then become dark as the train moves over the route in the manner hereinbefore described.

The secondary route 4 8 ovcr crossover S reversed may also be selected automatically under f' certain conditions, in accordance With a feature of my invention. as for example, when a Westbound train moving over route 8-2 vacates section ST, but steps in section iT so that relay ILR remains deenergized, holding crossover I locked normal. in that case relay SLR picks up when the westbound train vacates section ST and relay STR closes contact |24, Fig. 1E, but the preferred route circuit including relay IRR, Fig. 1C, is held open at contacts 41 and |il| of relays ILR and I RWP. Since switch 3 is not involved, relay SLR Will be energized, and if buttons dP and 3P are operated, as before, a secondary route circuit will be closed from terminal B, contact 39 of relay SPS, Fig. 1C, back contact its of relay BRS, front contact I'i of relay INWP, back contact ITI of relay iLR, thence over back contacts of relays I QPS, SBNR and SANR, through relay SRR, over front contact i112 of relay SLR, and back contacts of relays EPS and BRR, relay NR, front contact |73 of relay SLR. back contact 39 of relay IRR, relay VIBNR, front contacts Ifl and 29 of relays INWP and iRS. relay HR to terminal C. It will be seen that this route circuit can not be closed if the train in section |T is an eastbound train, be-

cause relay IES and consequently relay SLR will then be deenergized and its contact |12 will be open, but that if section IT is occupied by a westbound train, the route circuit for the secondary route over crossover 5 may be closed in response to the operation of route buttons l and 8.

I will next assume that buttons :iP and iP have been operated to clear signal fl-A; that a train has passed the signal and is occupying route 4-|9, and that the operator wishes to clear the call-on signal to permit a following train to enter the same route. Signal 4C not only governs trafc movements over route -8 as hereinbcfore described but also serves as a call-on signal for routes i-B and d-I), as Will be apparent from the signal network circuits of Fig. 1D. As in the case of route 4-8, when the first train entered section iT, the route circuit was released before relay 'ITZ closed its back contact 'lS, Fig. 1B. When this contact closes it bridges contact I3 of relay 'ETP and thc operator may then operate button 6P, and after relay ARS pic s up the operator will press button IGP to pick up relay ISPS to re-establish route -lil. The closing of contact 29 of relay IcFS, Fig. 1C, completes the route circuit from terminal B, contact 29 of relay IQPS, back contacts IGS and 31 of relays IGRS and SRR1 relay SBNR, front contact |16 of relay SNWP, back contacts of relays SPS and SRR, relay SNR, front contact |11 of relay 3NWP, back contact 39 or relay IRR, relay EBNR, front contacts |14 and 28 ci relays ARS and SHR to terminal C, so that relays SBNR, SNR, IBNR and llHR become energized. The corresponding signal circuit, Fig. 1D, is no'vf connected to terminal B over contact lli] of relay IGLS and theclosed contacts |19, |69, ii, S8 and |93 of relays SBNR, SNR, IBNR, AHR, ant INWl?` but is open at Contact |82 of relay STR or contact |83 of relay 1TR, so that mechanism llAG remains deenergized, relay AGP remains picked up and lamp R of indicator 4K remains lighted.

The operator then pushes button 4CP, Fig. 1B, completing` a circuit from terminal B, contact |94 of button flCP, relay llCOS, contact |85 of relay cAGP to terminal C, and relay 4COS picks up to complete a stick circuit over its own front Contact |85 and contact |82' of relay IlPS. Relay COS also completes a branch of the signal circuit just traced which extends from front contact 8B of relay AHR, Fig. 1D, over contacts |88 and 90 of relays ECOS and SAGP, mechanism ACG, contact 9| of relay l-IR to terminal C, thereby clearing signal 4C and releasing relays llCGP and lLS.

After the second train has passed the call-on signal 6C, the operator may cancel the route and restore the signal to stop by pulling button 4P to open contact il', Fig. 1B. Relay GCOS, however, remains energized over a stick circuit including its own front Contact I E26 and back contact |89 of relay ALS, and relay IlLS does not pick up when contact 53, Fig. 1F, of relay "CGP closes, because its pickup circuit over back contact IIT of relay 'ITP is now open at back contact I6 of relay COS. The time release of the locking is therefore effective, this feature operating as follows:

When signal 6C is restored to stop, a circuit is closed from terminal B, front contacts 93 and IM of relays QCGP and llAGP, back contact IIB of relay LS, back contact |99 of relay IITES, through the heating element of the thermal relay TE to terminal C. After a predetermined time, front contact IIS of relay TE closes to complete a pickup circuit for relay 4TES, which relay picks up and is held energized over its own front contact |90 and 'back Contact ||8 of relay ALS, deenergizing relay ATE by opening back contact |90. After a predetermined cooling time, back contact II of relay ATE closes to complete a pickup circuit for relay ALS over front Contact I9| of relay ATES, as will be apparent from the drawings. Relay ALS then picks up to complete a stick circuit from terminal B over its own front contact IIB, and releases relay ATES. Relay ATES upon releasing, closes the check contact 01, Fig. 1D, in the circuits for the signals which control relay ALS. It is to be noted that this time delay is nullied in case the approach section is unoccupied, because a pickup circuit for relay ALS is then closed over front contact |92 of relay AAR. The circuits for the other LS relays of Fig. 1F are generally similar, and it will be evident without further detailed description that they operate in each case in such ay manner as to prevent the operator from cancelling a route in the face of an approaching train and then immediately setting up a different route. Since each signal circuit in Fig. 1D includes a front contact such as contact 19 or |18 for the relay LS for'the opposing signal, it will be evident that a reversal of traic direction is also prevented under these conditions.

When a route has been cancelled and the time locking is eiective, it is desirable to inform the operator when the time vinterval ends and the locking becomes released. This is accomplished in accordance with a feature of my invention by causing the signal indicator to display aflashing red indication as long as the time locking is effective, as illustrated by the circuit for lamp R of indicator AK which includes back contact I3I of relay ALS, Fig. 1H, which has already been described.

Although I have described but a few of the many possible operations of this form of my apparatus,rit is believed that the operation of setting up other routes and also of setting up routes and clearing the signals for the opposite direction will be readily understood from the drawings without further description.

I will next consider the second form of my invention and assume that the intermediate signal I2 is provided in the system disclosed in the drawings of Figs. 1A, to 1H, inclusive. The relays` of Fig. 2 will now function in response to the operation of button |2P or of the signal control` relay 2I-IR or AI-IR, as will be described. Relay IES is not required, and it is to be understood that its contact 91a, Fig. 1E, is replaced by contact 97b of relay I2LS, and also that contact 6| of relay IESK, Fig. 1G, is omitted, relay BESK now being controlled by relays 2-8I-IS and I ZHS, as indicated on the drawings'. The back contacts of the relays RR in the crcuits for relays 2PS and APS may also be omitted because routes 2--I2 and AI2 in this form do not conflict with route 6 8. Assuming first that buttons AP and 8P are'operated to set up routev A--B as described in connection with the rst form of the apparatus, in this case when relay AHR picks up a cir'- cuit will be closed from terminal B, normal contact of button |2P, Fig. 2, front contact 202 of relay STP, back contact 203 of relay I'ZHS, front contacts 20A, 20E and 205 of relays AHR, IRR and SANR, relay 2-3I-IS to terminal C. Relay 2-8I-IS picks-up and closesits stick circuit from terminal B over contacts 20| and 202 and its own front contact 201,V and also closes contact 208 to pick up relay 2-8HSP.

Referring to Fig. 1C, it will be seen that the route circuit for route A-B initially includes back contact 209 of relay 2-8HS but that when this relay picks up4 the circuit is cut into two portions, the left-hand portion being connected to terminal B over front contact 209 and the righthand'portion to terminal C over contact 2I0 of relay 2-8I-IS, the continuity of the circuits being maintained while this relay is picking up because contact 209 is bridged by a circuit portion including resistor 2| I and back contact 2I2 of relay 2--0HSP, which opens as soon as the latter relay picks up. The corresponding signal circuit -ofFig. 1D is likewise cut into two portions, the right-hand portion being completed through mechanism I2G over front contacts 2I3 and 2IA of relay Z-SHSR while the left-hand portion isr connected to terminal B over front contact 2I5 of relay 2BHSP to energize mechanism ACG. It follows, therefore, that in this case, signals AC and I2 are both cleared, while if the same buttons are operated in the reverse order to pick up relay SHR, signal 8C will clear as in the first form of the apparatus.

I will next assume that with the apparatus as shown, buttons AP and IZP are operated in that order. Relays APS and ARS pick up as already described, and the operation of button I2P as an exit button completes a circuit from terminal B, contact 2|6 of button IEP, back contacts 2|'I and 2I8 of relays SHR and 2-8HS, relay IZPR to terminal C. Relay I 2PR picks up, closing contact 2I9, Fig. 1C, connecting terminal B to the left-hand portion of the route circuit to energize relays IRR and AHR only, and relay IRR closes contact 220, Fig. 2, to complete a circuit from terminal B, contact 20| of button IEP, contacts 222 and 220 of relays I2PR and IRR, relay IZXS to terminal C. Relay I ZXS picks up to complete a stick circuit from terminal B over contact 20| and its own front contact 224 and front contact 220 of relay IRR. Relay I'ZPR releases when button I2P is released, but relay IZXS closes contact 225, Fig. 1C, to maintain the route circuit closed until contact 28 lof relay ARS opens, as in the first form. Relay IZXS also completes a connection from terminal B, front contact 220 of relay SWS, Fig. 1D, front contact 22'! of relay IZXS, thence as hereinbefore described over contacts 88 and 9| of relay AHR through mechanism ACG to terminal C. In this case, signal AC will clear, but the train passing this signal will be held by signal I.2 at stop.

I will next assume that signal AC has been cleared by an operation of buttons AP and I2P, and that while signal AC is at clear, buttons I2P and 8P are operated in that order. It will be noted that when relay IZPR released, after its rst operation, a circuit was closed from terminal B, front contact 228 of relay I ZXS, back contact 229 of relay I2PR, relay IZCK to terminal C, and that relay I2CK is now energized over a stick circuit from terminal B over contact 228 and its own front contact 230. The second operation of relay |'2PR therefore completes a circuit from terminal B, front contacts 23|, 232 and 233 of relays |2PR, IZCK and I2XS, back contacts 23A and 235 of relays SANR and ERR, front contact 236 of relay SLR or front contact 237 of relay ENWP, relay |2HS to terminal C, so that relay |2HS picks up to complete a stick circuit from terminal B, Contact 20| of button I2?, contact 202 of relay ETP, front contact 203 and winding of relay I2HS to terminal iC. Relay IZHS closes contact 238, Fig. 1C, to

complete the route circuit to terminal C for relay SANR, and also closes contacts 239 and 240, Fig. 1D, to complete the signal circuit for mechanism |2G, to clear signal |2. It will be apparent, therefore, that signals 4C and I2 may be cleared either by an operation of buttons 4P and P or by an operation of buttons 4P and I2P` followed by an operation of buttons IZP and 8P.

I will now assume that signal 4C has been cleared by an operation of buttons 4P and I2P and that a train has passed signal 4C and is approaching signal I2. The release of relay 'ITR has caused the release of relays ITP, 4PS, 4RS, IRR, IZXS, IZCK and 4I-IR and of mechanism 4CG. If buttons IEP and 8P are now operated in that order, I2PR will become energized to complete a circuit from terminal B, front contact 23| of relay IZPR, back contacts 24|, 242, 233, 234, 235 of relays IANR, IRR, IZXS, EANR, SRR, front contact 235 of relay LB or front contact 231 of relay 5NWP, relay IRI-IS to terminal C, so that relay IZI-IS will pick up to effect the clearing of signal I2 and the operation of crossover 5 if required, as in the preceding example. In either case, when relay IZHS is energized, relay SANR will become energized over Contact 30 of relay SPS, and will open back Contact 234 in the pickup circuit of relay IZHS so that the latter relay will release when the train passes signal I2 and causes contact 202 of relay ETP to open.

It will be apparent from the foregoing that relay IZXS serves solely as an exit relay for the route portions 4--I2 or 2-|2, while relay I2HS serves solely as an entrance relay for the route portion |2-0, and that relays 2-0HS and 2-8HSP serve to clear signal I2 along with signal 4 or signal 2 when the route buttons 4P and( SP or 2P and 8P are operated. It is also to be understood that similar arrangements may be readily provided for the opposite direction in case it is desired to provide an intermediate signal for governing the movement of traflic from right to left into the route portions I2-2 or |2-4.

CII

Ll (l Since signal I2 is cleared only in response to the energization of relay Z-SHS or relay I2HS, it will be evident that the front contacts 243 and 244 of these relays shown in Fig. 1G serve to properly control the indication relay 5ESK in place of Contact 0I of 4relay IESK, and that contacts 245 and 246 of these relays shown in Fig. 1H serve to properly control the circuits for lamp R of indicator IZK, and that the signal and track indicators will function in the second form of the apparatus in a manner consistent with the operation of the rst form, as hereinbeore described.

Considering now the third form of my apparatus, it is to be understood that in this form Fig. 3A replaces the corresponding portion of Fig. 1C, the remaining apparatus of Figs. 1A to 1H being similar to that already described. Fig. 3A illustrates the route circuits for the two alternate routes 4 8 which dil-fer from those of Fig. 1C in that they include contacts 30| and 302 of a stick relay 4-8TES, which relay is controlled by a thermal relay 41TE in the manner illustrated in Fig. 3B. l

Assuming these relays to have been provided, if buttons 4P and ISP are operated as hereinbefore described, when relays PS and 0PS pick up a circuit is closed from terminal B over front contacts 303, 304, 305 and 305 of relays 4CGP, SCGP, 4PS and BPS, back contact 301 of relay 4-BTES, through the heating element of the thermal relay 4--STE to terminal C. Normally signal 4C or 0C will clear before relay 4-0TE closes its front contact 308 and then contact 303 or 304 will open to restore relay 4-8TE to its normal cooled condition, but if for any reason the preferred route 4 3 over crossover fails to be completed within a predetermined time, contact 308 closes completing a pickup circuit through relay 4--8TES to terminal C, whereupon this relay picks up closing a stick circuit from terminal B over its own front contact 309, front contacts 305 and 306 of relays IPS and SPS and its own front contact 301, and also opens back contact 30| in the preferred route circuit of Fig. 3A and closes front contact 302 to complete the secondary route circuit. The selection of the secondary route circuit is thereby effected automatically at the end of a predetermined time whenever thc preferred route fails to become established, and relay 4-8TES is then held energized until a train enters the route and relays 4PS and BPS release. This method of selection obviously can be further extended to effect the selection of one or more additional routes one at a time in order when such routes are provided by the track layout, each route being selected in the event the preceding one is not completed within a predetermined time.

In Fig. 4, I have illustrated means whereby the directional route relay RS at the entrance end of a route is operated automatically by an approaching train, so that the operation of the route button at that end of a route is rendered unnecessary in the event a train occupies the corresponding approach section. AIn the fourth form of my apparatus, vwhich I will now describe,

it is to be understood that circuits similar to those -of Fig. 4 replace the circuits for controlling one or more of the pairs of relays PS and RS of Fig. 1B in the rst form of the apparatus, the circuits of Fig. 4 as shown, being arranged to replace those controlled by button 4P in Fig. 1. Fig. 4 includes circuits for picking up relays 4PS and 4RS successively when button 4P is operated as an entrance button, and circuits for picking up lIPS only when button 4P is operated as an exit button, and also includes circuits forlreleasing these relays manually or when a train enters the route, which are similar to those of Fig. 1B. In addition, Fig. 4 includes a momentary pickup circuit for relay 4RS which circuit is controlled by the approach relay 4AR and by a slow-acting repeater relay 4ARP. Relay 4ARP is normally energized over a circuit extending from terminal B, contact I1 of button 4P, front contacts 40| and 402 of relays 'ITP and 4AR, relay 4ARP to tere minal C. AWhen a train moving from left to right enters section 4T, relay 4AR releases, as herein-A before described, and completes a circuit momentarily from terminal B over the normally'closed contact I1 of button 4P, front contact 40| of relay TTF, back contact 402 of relay 4AR, front Contact 403 of relay 4ARP, back contact 23of relay 4PS, relay 4RS to terminal C. The duration of this impulse is made suiiicient to insure that relay 4RS will pick up to close its stick circuit, which includes its own front contact 404'in place of Contact; 403 but otherwise is the same as the circuit 'just traced. Contacts I3 and 31 of relays 4AR and Aas, Fig. 1H, compiere the circuits for lamps R of indicators 4AK and 4K, and since front contact 28 of relay 4RS, Fig. 1C, is closed, the route circuits for routes-4 8 and 4"-I0 are connected to relay 4HR and buttons 8P and 0P are conditioned to function as exit buttons only. It will be clear, therefore, that when section 4T is occupied by an approaching eastbound train the operation of button 4P as an entrance button is not required, but that the operation of button 8P only or button IUP only will complete the route circuit for route 4-8 or 4| and clear the corresponding signal 4C or 4A. If the operator does not wish to set up the route for the train in section 4T at this time, but desires rst to use button 8P orV IP as an entrance button to set up route 8-6 or Ill-5, for example, he will pull button 4P to open contact l1 momentarily to release relay lflRS before operating button 8P or IOP. It is also to be noted that in Fig. 4 relay IRS does not pick up when a departing westbound train enters section 4T because in this case contacts 40| and 403 of relays 'ITP and AARP are opened before back contact 452 of relay AR closes. In the particular case illustrated, it is necesasry also to provide auxiliary means for opening fthe secondary route circuit for route 4 8, when the preferred route 4-8 is set up without operating relay GPS, which as shown in Fig. 4, comprises a back contact 405 of relay liRS in series with the back Contact 3| of relay 4PS which serves for this purpose in the first form of the' apparatus. It is to be understood, therefore, that in the fourth form of the apparatus, contacts 3| and 405 in series replace contact 3| of relay 4PS in Fig. 1C; It will be apparent from the foregoing description that the fourth form of my apparatus provides means whereby an approaching train may be directed over any one of a plurality of diverging routes merely by momentarily operating a single push button associated with the exit end of the desiredV route. l

Although I have herein shown and described but a few forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. In an interlocking system for railroads, a

track layout comprising a plurality of track sections interconnected by track switches to form diierent trailic routes, a signal for each track at each end of the layout for governing the movement of traffic through the layout, a track diagram comprising a plurality of portions provided with substantially linear light sources and adapted to form an illuminated,representation of said track layout, a manually operable contact for each track at each end of the diagram, interlocked route control means responsive tovthe manual operation of a Contact at one end and the subsequent operation of a contact at the opposite end of the diagram to operate the track switches as required to complete a traflic route between the corresponding ends of the track layout, means effective when said route is completed to illuminate certain portions :of said diagram to visually indicate said route by a substantially continuous illuminated line, means controlled by said route control means for clearing the signal at one end of the route or the other, 'depending upon the relative order in which said contacts were closed, track controlled means for illuminating the portions o-f the diagram corresponding to said route by light of a different color to indicate the movement of a train over the successive track sections of the route, means cancelling the illuminati-on of the corresponding portions of the diagram as each track section is vacated, and track controlled means for releasing said route control means to cancel said route and to restore-the cleared signal to stop when the train enters the iirst track section of the route.

2, In combination, a detector section of railwayv track including a track switch, a track relay controlled by the track switch and by a back contact of the track relay for at times illuminating said portion by light'zof a different color to indicate that'said route is occupied by a train.

3. In combination, a detector section of rail-A way track including a track switch, a track diagram comprising a plurality `of substantially linear translucent portions arranged to form ar miniature representation of said track including one portion flor each branch track-extending in y the trailing direction from the track switch and a portion for the single track extending in the facing direction from the track switch, manually controlled means for at times illuminating one or the other of said branch track portions in accordance with the position of the track switch and for also illuminating said single track portion to indicate by a substantially col'itinuousk illuminated line the available route through the detector section, means rendered effectivewlienV 'the detector section becomes occupied by a train for changing the character of said illumination to indicate the presence lof the train, and means for automatically cancelling said illumination when the detector section becomes vacated.

4. In combination, a detector section of railway track including a' track switch, a track diagram comprising a plurality of portions arranged to form a miniature representation of said detector section, two lamps of different colors for eachportion for illuminating such portion, manually controlled means effective if operated whenV the detector section is unoccupied to light one lamp for each portion, and means rendered effectivewhen the detector section becomes occupied to extinguish said one lamp for each portion and to light the other lamp for each portion.

5. In combination, a detector section of railway track including a track switch, a track diagram comprising a plurality of portions arranged to form a miniature representation of said detector section, two lamps of different colors for each portion for illuminating such portion, manually controlled means effective if operated when the detector section is unoccupied to lightone lampfor each portion, means effective when the detector section becomes occupied to extinguish said one lamp for each portion and tolight the other lamp foreach portion, and means elective when the detector section is vacated to extinguish l said other lamp for each portion.

6. In combination, a track layout comprising a plurality of track sections interconnected by track switches to form 'different traffic routes, a track diagram comp-rising a plurality of portions arj ranged to form a miniature representation of said layout, two lamps of different colors for each portion for illuminating such portion, control means for establishing different traflic routes through said layout, means eiective when a route is established through said layout to light one lamp for each portion of the corresponding route on said diagram, means effective when each track section of said route is occupied to extinguish the lamps for the corresponding portions of the route and to then light the other lamps for such portions, and means effective when each track section of said route is vacated for extinguishing such other lamps.

'7. In combination, a track layout comprising a plurality of track sections interconnected by track switches to form differentY traine routes, a track diagram arranged, to form a miniature representation of said layout, lamps f two colors for illuminating the tracks of said diagram, control means for establishing different traiiic routes through said layout, means effective when a route is established to light the corresponding lamps of one color to visually indicate such route on said diagram, `means effective as each track section of said route becomes occupied to light the lamps of the other color only to illuminate the corresponding section of the diagram, and means eii'ective as each track section is vacated to cause the corresponding section of the diagram to become dark.

8. In combination, a track layout comprising a plurality of track sections interconnected by track switches to form different traffic routes, a track diagram composed of strips of translucent material` arranged to form a miniature representation of said layout, control means for establishing different traflic routes through said layout, means effective when a route is established to illuminate the strips which form the representation oi the corresponding route by light of one color, means effective as each track section of said route becomes occupied to illuminate the strips which form the representation of that section by light of another color, and means effective as each track section is vacated to cause the representation of that section to become dark.

9. In combination, a track layout comprising a plurality of track sections interconnected by track switches to form different tranc routes, a signal at each route and at each end of said layout, a track diagram arrangedv to form a miniature representation of said layout including two indication lamps of diierent color for each signalin a corresponding location, control means for establishing diierent traffic routes through said layout and for clearing the signals for such routes, means effective when said control means is operated for clearing a signal to light the corresponding indicationlarnp of one color only, and means responsive to the clearing of such signal for lighting the corresponding indication lamp of the other color only.

10. In an interlocking system for railroads, a track layout comprising Va plurality of track sections interconnected by track switches to form different trafc routes, a track relay and a stick relay for each track section, control means for each route eiective when energized to opera-te the track switches as required to establish such route, means for maintaining said control means energized until the entering section of said route becomes occupied, means for energizing the stick relay for said entering section when said control means is operated, means for energizing the stick relays for each of the succeeding sections of said route, each whenfthe stickrelay for the next preceding section of said route becomes energized, a holding circuit for each stick relay closed when the track relay for the same section in deenergized, and route indication means controlled by said stick relays.

1l. In an interlocking system for railroads, a track layout comprising a plurality of track sections interconnectedby track switches to forni different traffic routes, a track relay and a stick relay for each track section, control means for each route effective when energized to operate the track switches as required to establish such route, means for maintaining said control means energized until the entering section of said route becomes occupied, means for energizing the stick relay for said entering section when said control means is operated, means for energizing the stick relays for each of the succeedin(T sections of said route, each when the stick relay for the next preceding section of said route becomes energized, a holding circuit for each stick relay closed when the track relay for the saine section is decnergized, route indication means controlled by` front contacts of said stick relays and of said track relays, and track indication means controlled by front contacts of said stick relays and by back contacts of said track relays.

12. In an interlocking system for railroads, a track layout comprising a plurality of track sections interconnected by track switches to form different traic routes, a track relay and a stick relay for each track section, control means for each route effective when energized to operate the track switches as required to establish such route, means for maintaining said control means energized until the entering section of said route becomes occupied, means for energizing the stick relay for said entering section when said control means is operated, means for energizing the stick relays for each of the succeeding sections of said route, each when the stick relay for the next preceding section of said route becomes energized, a holding circuit for each stick relay closed when the track relay for the same section is deenergizedya track diagram comprising a miniature representation or the track layout, two sets of lamps of different color for illuminating the tracks of said diagram to indicate diierent trafc routes through said layout including one or more lamps of each set for each track section, means controlled by front `contacts of the track relays and of` said stick relays to light those lamps of one set which correspond to the route established by the energized control means, and means controlled by back contacts of each track relay for lighting certain lamps of the other set to indicate the occupancy of the corresponding track section. Y

13. In an vinterlocking system for railroads, a track layout comprising a plurality of track sections interconnected by track switches to form different traffic routes, a track diagram comprising a miniature representation of the track layout, a plurality of lamps included in the tracks of said diagram for displaying illuminated representationsr of the different routes through said layout, route control means for each route effective when energized to operate one or more of the track switches as required to establish said route, an indication relay for each track section, means controlled by said. Yroute control means when energized to successively energize in tandem the indication relays for the successive sections of the corresponding route only, and means controlled by said indication' relays and bythe track switches for lighting certain of said lamps to indicate the portions of said route that are already established and for lighting the remaining lamps for said route when the operated switches assume their operated positions to 4thereby indicate a complete lroute on said diagram as 4soon as said route is fullyV established through said track layout.

14. In an interlocking system for railroads, a track-layout comprising a plurality of track sec- -tions interconnected by track switches to form different traiiic routes, a track diagram comprising a miniature representation of the track layout, Va plurality of lamps included in the tracks of said diagram for displaying illuminated representations of the different routes through said layout, route control means foreach route eective `when energized to operate one or more of the track switches as/required to Yestablish said route, and-indication relay for each track section, means controlled by said route control means when energized to successively energize intandem the indication relays for the successive sections of the corresponding route only, a track relay for each track section, means controlled by each track relay for maintaining the indication relay for the corresponding track section energized until such section is vacated by a train moving over the established route, and means controlled by said indication relays and track relays for controlling the corresponding lamps of said track diagram to indicate the progress of the train over said route.

15. In an interlocking system for railroads, a plurality of traic routes through a track layout, a manually operable contact for each route end for each end oi the layout, means responsive to the successive momentary operation of the contacts for the opposite ends of a route to establish that route through the layout, and means dependent only upon the relative order in which such contacts are operated for determining ythe direction of traiiic movements over that route when established.

16. In combination, a track layout comprising a plurality of track sections interconnected by track switches to form different trafc routes, a manually operable contact for each route end for each end of th'e layout, means responsive to the successive momentary closing of the two contacts for the opposite ends of a route to establish that route through the layout, means dependent only upon the relative order in which said contacts are closed for determining the directionof traffic movements over that route when established, and means for automatically cancelling the established route when a train enters the first track section of that route.

17. In combination, a plurality of traffic routes through a track layout, a centrally biased threeposition manually operable circuit controller for each route end for each end of the layout, means responsive to the successive momentary operation of the circuit controllers for the opposite ends of a route to their first operating positions to establish that route through the layout, means dependent only upon the relative order in which said controllers are operated for determining the traic direction over that route when established, and means for cancelling said route in response to a movement of one controller to its other operating position.

18. In combination, a plurality of trafiic routes through a track layout, a push button for each route end for each end of the layout, each provided with a single contact closed when such button is operated, a route relay for each push button, each effective when yoperated to select the corresponding direction for tramo movements through the layout, means effective if a push button for one end of the layout is operated to Aoperate the associated route relay provided said push button is operated before any push button for the opposite end is operated, and means effec- -tive to Yestablish the route connecting the corresponding route ends o the layout if such push button is ope-rated after a push button and route V.relay for the opposite end of the layout have been operated.

19. In an interlocking system vfor railroads, a plurality of routes through a track layout, a signal for each'track at each end of the layout for governing the movement of tramo over said routes, a single normally open manually operable contact for each route end for each `vend -of the layout, means responsive to the momentary closing in sequence of the two contacts for the opposite ends of a route to establish that route through the layout, and means dependent only upon the relative order in which said contacts are closed and eiective when that route is established to selectively clear one or the other of the two opposing signals for governing the movement of traflic over that route.

20. In an interlocking system for railroads, a track layout comprising a plurality of track sections interconnected by track switches to form different traiiic routes, a signal for each track at each end of the layout for governing the movement of traiiic over said routes, a track relay for each section, route -control means for each route, a manually operable contact for -each route end for eac-h end -of the layout, means responsive to the -momentary closing in sequence of the two contacts for the opposite ends of a route to energize the route control means vfor that route, means controlled by said route control means for operating one or more of the track switches as required `to establish that route, means dependent only upon -the relative order in which said contacts are closed and eiective when said route is established to selectively clear one or the other of the two Vopposing signals for governing the movement of traino over that route, and means controlled by the track relay for the entering track section of that route for automatically releasing said route control means.

2l. In an interlocking system for railroads, a railway track switch operable to normal and reverse-positions, signals for governing the movement of trafic over said switch in each of its positions in opposite directions, whereby either of two routes may be set up to permit a train to move in either direction over the switch, a push button for each of said signal locations, means responsive to the operation of the push `button for one end of a route followed by the operation of the pushbutton for the opposite end of said route for automatically operating the track switch-to a proper normal or reverse position for that route, and means dependent only upon the relative order of operation of said push buttons for clearing the signal at that end of the route which corresponds in location to the push button which was operated first.

22. 'In an interlocking system for railroads, a track layout comprising a plurality of track sections interconnected by track switches to form di-ierent traflic routes, a plurality of signals for governing the movement of traino through said layout in opposite directions, a miniature track diagram corresponding to said track layout, a push button on said track diagram for each of said signals and in a corresponding position, means responsive `to the actuation in sequence of the two push buttons at the opposite ends of a route to operate one or more of the track switches as required to establish that route and to then clear one of the two opposing signals governing the movement of traiiic over that route, and means dependent only upon the relative order in which said push buttons were actuated for determining which of said two signals is to be cleared.

23. In an interlocking system, a track layout comprising a plurality ,of track sections interconnected by track switches to form different traiiic routes, a normal control relay and a reverse control relay for each switch, a route network comprising a plurality of interconnected circuits each corresponding to one of said routes and each of which includes in series the winding of the normal or reverse control relay for each switch in the corresponding route, a manually controllable contact for each route end for each end of said network, means responsive to the successive operation of the contacts for the opposite ends of a route to energize the network circuit for said route for operating the switch control relays to establish said route, and means dependent only upon the relative order in which said contacts are closed for determining the direction of trailic movements over said route when established.

24. In an interlocking system, a track layout comprising a plurality of track sections interconnected by track switches to form different traino routes, a normal control relay and a reverse control relay for each switch, a route network comprising a plurality of interconnected circuits each corresponding to one of said routes and each of which includes in series the winding of the normal or reverse control relay for each switch in the corresponding route, a stick relay for each route end at each end of said network, a pickup circuit for each stick relay including a manually operable contact, means responsive to the successive energization of the stick relays at the opposite ends of a route to energize the network circuit for said route thereby operating the switch control relays to establish said route, and means controlled by said switch control relays for maintaining said stick relays energized until the entering track section of said route becomes occupied by a train or said route is manually cancelled.

25. In an interlocking system, a track layout comprising a plurality of track sections interconnected by track switches to form diierent trailic routes, a normal control relay and a reverse control relay for each switch, a route circuit network comprising a plurality of interconnected route circuits each corresponding to one of said routes and each of which includes in series the winding of the normal or reverse control relay for each switch in the corresponding route, a manually operable route button for each route end at each end of said network, a stick relay for each route end having a pickup circuit controlled by the associated route button, means responsive to the successive energization of the stick relays at the opposite ends of a route to energize the network circuit for said route thereby operating the switch control relays to establish said route, and means including a back Contact of one of said switch control relays for preventing the energization of the stick relay for the end a conilicting route.

26. In an interlocking system for railroads, a plurality of railway tracks interconnected by track switches to form a plurality of traiiic routes. a manually controllable contact and a slow pickup route relay for each route end, a route network comprising a plurality of interconnected circuits each corresponding to one of said routes, means for energizing the route relay for one end of a route when the associated manually controllable contact is closed, means responsive to the closing of the manually controllable contact for the other end of said route after said route relay has picked up for energizing the network circuit for said route, means controlled by said network circuit when energized to prevent the pickup of the route relay for said other end even though the associated manually controllable contact is closed and to also operate the track switches as required to establish said route, and means controlled by the energized route relay for for controlling the direction of traic movements over said route when established.

27. In combination, a plurality of traffic routes through a track layout, a manually controllable relay for each route end for each end of the layout, means rendered effective to select the corresponding direction for traffic movements through the layout if one of said relays becomes energized before any of said relays for the opposite end of the layout is energized, and means rendered eiective to establish the route connecting the corresponding route ends of the layout if such relay becomes energized after one of said relays for the opposite end of the layout has been energized.

28. In combination, a plurality of tranic routes through a track layout, a manually controllable stick relay and a route relay for each route end for each end of the layout, means for energizing each route relay when the associated stick relay becomes energized provided no stick relay for the opposite end of the layout is energized, and means responsive to the energization of a stick relay for one end of the layout after a route relay for the opposite end of the layout has been energized for establishing the route connecting the corresponding route ends of the layout to permit a traiiic movement in the corresponding direction.

29. In combination, a plurality of traffic routes through a track layout, a manually controllable stick relay and a route relay for each route end for each end of the layout, means for energizing each route relay when the associated stick relay becomes energized provided no stick relay for the opposite end oi the layout is energized, means responsive to the energization of a stick relay for one end of the layout after a route relay for the opposite end of the layout has been energized for establishing the route connecting the corresponding route ends of the layout to permit a trafc movement in the corresponding direction, track controlled means for releasing the stick relay which governs the energized route relay, and means controlled by such route relay when released to release the stick relay for the opposite end of the route.

30. In an interlocking system for railroads, a track layout comprising a plurality of track sections interconnected by track switches to form different traffic routes, a manually controllable stick relay and a slow pickup route relay for each route end, a route network comprising a plurality of interconnected circuits each corresponding to one of said routes, means for energizing the route relay for one end of a route 

